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  <div class="section" id="add-compile-options">
<span id="command:add_compile_options"></span><h1>add_compile_options<a class="headerlink" href="#add-compile-options" title="Permalink to this headline">¶</a></h1>
<p>Add options to the compilation of source files.</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">add_compile_options(</span><span class="nv">&lt;option&gt;</span><span class="w"> </span><span class="p">...</span><span class="nf">)</span><span class="w"></span>
</pre></div>
</div>
<p>Adds options to the <span class="target" id="index-0-prop_dir:COMPILE_OPTIONS"></span><a class="reference internal" href="../prop_dir/COMPILE_OPTIONS.html#prop_dir:COMPILE_OPTIONS" title="COMPILE_OPTIONS"><code class="xref cmake cmake-prop_dir docutils literal notranslate"><span class="pre">COMPILE_OPTIONS</span></code></a> directory property.
These options are used when compiling targets from the current
directory and below.</p>
<div class="section" id="arguments">
<h2>Arguments<a class="headerlink" href="#arguments" title="Permalink to this headline">¶</a></h2>
<p>Arguments to <code class="docutils literal notranslate"><span class="pre">add_compile_options</span></code> may use “generator expressions” with
the syntax <code class="docutils literal notranslate"><span class="pre">$&lt;...&gt;</span></code>.  See the <span class="target" id="index-0-manual:cmake-generator-expressions(7)"></span><a class="reference internal" href="../manual/cmake-generator-expressions.7.html#manual:cmake-generator-expressions(7)" title="cmake-generator-expressions(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">cmake-generator-expressions(7)</span></code></a>
manual for available expressions.  See the <span class="target" id="index-0-manual:cmake-buildsystem(7)"></span><a class="reference internal" href="../manual/cmake-buildsystem.7.html#manual:cmake-buildsystem(7)" title="cmake-buildsystem(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">cmake-buildsystem(7)</span></code></a>
manual for more on defining buildsystem properties.</p>
<p>The final set of compile or link options used for a target is constructed by
accumulating options from the current target and the usage requirements of
its dependencies.  The set of options is de-duplicated to avoid repetition.
While beneficial for individual options, the de-duplication step can break
up option groups.  For example, <code class="docutils literal notranslate"><span class="pre">-D</span> <span class="pre">A</span> <span class="pre">-D</span> <span class="pre">B</span></code> becomes <code class="docutils literal notranslate"><span class="pre">-D</span> <span class="pre">A</span> <span class="pre">B</span></code>.  One may
specify a group of options using shell-like quoting along with a <code class="docutils literal notranslate"><span class="pre">SHELL:</span></code>
prefix.  The <code class="docutils literal notranslate"><span class="pre">SHELL:</span></code> prefix is dropped, and the rest of the option string
is parsed using the <span class="target" id="index-0-command:separate_arguments"></span><a class="reference internal" href="separate_arguments.html#command:separate_arguments" title="separate_arguments"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">separate_arguments()</span></code></a> <code class="docutils literal notranslate"><span class="pre">UNIX_COMMAND</span></code> mode.
For example, <code class="docutils literal notranslate"><span class="pre">&quot;SHELL:-D</span> <span class="pre">A&quot;</span> <span class="pre">&quot;SHELL:-D</span> <span class="pre">B&quot;</span></code> becomes <code class="docutils literal notranslate"><span class="pre">-D</span> <span class="pre">A</span> <span class="pre">-D</span> <span class="pre">B</span></code>.</p>
</div>
<div class="section" id="example">
<h2>Example<a class="headerlink" href="#example" title="Permalink to this headline">¶</a></h2>
<p>Since different compilers support different options, a typical use of
this command is in a compiler-specific conditional clause:</p>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">if</span> <span class="nf">(</span><span class="no">MSVC</span><span class="nf">)</span><span class="w"></span>
<span class="w">    </span><span class="c"># warning level 4 and all warnings as errors</span>
<span class="w">    </span><span class="nf">add_compile_options(</span><span class="na">/W4</span><span class="w"> </span><span class="na">/WX</span><span class="nf">)</span><span class="w"></span>
<span class="nf">else()</span><span class="w"></span>
<span class="w">    </span><span class="c"># lots of warnings and all warnings as errors</span>
<span class="w">    </span><span class="nf">add_compile_options(</span><span class="p">-</span><span class="nb">Wall</span><span class="w"> </span><span class="p">-</span><span class="nb">Wextra</span><span class="w"> </span><span class="p">-</span><span class="nb">pedantic</span><span class="w"> </span><span class="p">-</span><span class="nb">Werror</span><span class="nf">)</span><span class="w"></span>
<span class="nf">endif()</span><span class="w"></span>
</pre></div>
</div>
</div>
<div class="section" id="see-also">
<h2>See Also<a class="headerlink" href="#see-also" title="Permalink to this headline">¶</a></h2>
<p>This command can be used to add any options. However, for
adding preprocessor definitions and include directories it is recommended
to use the more specific commands <span class="target" id="index-0-command:add_compile_definitions"></span><a class="reference internal" href="add_compile_definitions.html#command:add_compile_definitions" title="add_compile_definitions"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">add_compile_definitions()</span></code></a>
and <span class="target" id="index-0-command:include_directories"></span><a class="reference internal" href="include_directories.html#command:include_directories" title="include_directories"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">include_directories()</span></code></a>.</p>
<p>The command <span class="target" id="index-0-command:target_compile_options"></span><a class="reference internal" href="target_compile_options.html#command:target_compile_options" title="target_compile_options"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_compile_options()</span></code></a> adds target-specific options.</p>
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  <ul>
<li><a class="reference internal" href="#">add_compile_options</a><ul>
<li><a class="reference internal" href="#arguments">Arguments</a></li>
<li><a class="reference internal" href="#example">Example</a></li>
<li><a class="reference internal" href="#see-also">See Also</a></li>
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